1. Technical Field
Exemplary embodiments relate to semiconductor devices and methods of tuning phase of a data clock signal, and memory controllers and memory systems using the same.
2. Description of the Related Art
Recently, operating speeds of semiconductor memory devices have become increasingly fast. As a result of the increased operating speed, phase mismatches between output data and data clock signals occur more frequently. Data training or clock and data recovery (CDR) is used in the semiconductor memory devices to remedy these phase mismatches.